Recognizing the importance of multinational telecollaboration and form-focused instruction in computer-assisted language learning teacher education, this article investigates teaching English grammar through a seven-week-long telecollaborative project with 41 pre-service language teachers from the United States (US), Poland, and China. The telecollaboration was a pedagogical intervention in which the US participants taught grammar to their non-native-speaker peers. Specifically, the study aimed to trace pre-service teachers' grammar instruction techniques applied in the communication-oriented context of online exchanges and responses to this instruction, the grammar forms attended to in the exchanges, and the participants' evaluations of the usefulness of telecollaboration for teaching and learning grammar. Utilizing data from the participants' emails and results of a post-project survey, this mixed methods study reveals that (1) the implicit technique of modeling was the most frequently applied; (2) the grammatical forms used in both implicit and explicit teaching reflected the communicative orientation of the exchanges; (3) the levels of uptake (i.e. attempts to follow the models provided in the input), and the forms attended to by the learners, reflected their proficiency levels and linguistic background; and (4) participants reported positive opinions about the value of telecollaboration in grammar instruction and in teacher training. The data thus underscore the benefits of online exchanges in giving prospective teachers hands-on experience with communicative grammar teaching.